```typescript index.ts
import { Mastercard } from 'mastercard-typescript-sdk';

const mastercard = new Mastercard({
    // The "Finicity-App-Key" from the developer dashboard
    finicityAppKey: "FINICITY_APP_KEY",
    // A token returned by the `/authentication` API
    finicityAppToken: "FINICITY_APP_TOKEN"
})
```